CronSchedule.weekendAt constructor
Builder: Weekends at specific time
Example: CronSchedule.weekendAt(hour: 10) → 10 AM on Sat/Sun
Implementation
factory CronSchedule.weekendAt({required int hour, int minute = 0}) {
if (hour < 0 || hour > 23) throw ArgumentError('Hour must be 0-23');
if (minute < 0 || minute > 59) throw ArgumentError('Minute must be 0-59');
return CronSchedule('$minute $hour * * 0,6');
}